Fructosamine measurement in ponies: validation and response following experimental cyathostome infection

Morphometric Patterns and Blood Biochemistry of Capybaras (Hydrochoerus hydrochaeris) from Human-Modified Landscapes and Natural Landscapes in Brazil

The capybara, Hydrochoerus hydrochaeris, is the largest extant rodent of the world. To better understand the correlation between size and body mass, and biochemical parameters of capybaras from areas with different degrees of anthropization (i.e., different food supplies), we sampled free-ranging capybaras from areas of natural landscapes (NLs) and human-modified landscapes (HMLs) in Brazil. Analyses of biometrical and biochemical parameters of capybaras showed that animals from HMLs were heavier (higher body mass) than those from NL, a condition possibly related to fat deposit rather than body length, as indicated by Body Condition Index (BCI) analyses. Biochemical parameters indicated higher serum levels of albumin, creatine kinase, cholesterol, fructosamine and total protein among capybaras from HMLs than from NLs; however, when all adult capybaras were analyzed together only cholesterol and triglycerides were positively correlated with body mass. We propose that the biochemical profile differences between HMLs and NLs are related to the obesity condition of capybaras among HMLs. Considering that heavier animals might live longer and reproduce more often, our results could have important implications in the population dynamics of capybaras among HMLs, where this rodent species is frequently represented by overgrowth populations that generate several levels of conflicts with human beings.

Biochemical, endocrine, and histopathological profile of liver and kidneys of sheep with pregnancy toxemia

ABSTRACT: The objective of the present study was to characterize the biochemical, hormonal, and mineral profile, and histopathology of the liver and kidneys, related to the severity of natural cases of pregnancy toxemia (PT) in sheep. A total of 45 sheep with PT were analyzed at the “Clínica de Bovinos”, Campus Garanhuns-UFRPE. The animals were submitted to clinical examination, followed by the collection of blood and urine. A necropsy was performed on thirteen animals that died and a histopathological examination was performed on samples of liver and kidneys. Increased creatinine, urea, glucose, fructosamine, non-esterified fatty acids, β-hydroxybutyrate, cortisol, chlorine, amylase, aspartate aminotransferase, gamma-glutamyltransferase, and folic acid were found, whereas insulin, potassium, and total and ionizable calcium presented low values for the species. Total protein, albumin, globulin, sodium, magnesium, and vitamin B12 remained within the normal range. In the macroscopic analysis of the liver, it was possible to observe an increase in organ and border size, yellowish coloration and parenchyma that varied from firm to friable. Vacuolation of the hepatocytes and renal tubular cells was observed. Metabolic disorders in sheep associated with hepatic and renal lesions are more apparent in overweight animals. With the greater impairment in hepatic and renal function, the clinical prognosis of animals with a high body score should be considered reserved.

Temporal relationships of GH, IGF-I and fructosamine concentrations in pregnant Spanish Purebred mares: A substantial contribution from the hormonal standpoint

Growth hormone (GH) and insulin-like growth factor (IGF-I) exert essential functions to maintain an adequate metabolic activity for correct placental and fetal development. Although fructosamine (FRUCT) is used in clinical evaluation to assess the glycaemic state, the relationships between GH, IGF-I and FRUCT remain unknown in the mare. Therefore, the objectives of this study were to evaluate the relationships among these parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares, with an age range of 9.33 ± 3.31 years, were studied during the 11 months of gestation. Serum concentrations of GH, IGF-I and FRUCT were analyzed by EIA, competition ELISA and spectrophotometry, respectively. GH showed a biphasic pattern, the first occurred during 4th and 5th month and the second which was higher than the 1st one during the 7th, 8th and 9th month (P < 0.05). Compared to the 1st month, the IGF-I concentrations increased in the 2nd month (P < 0.05), decreased in the 3rd and 4th month and increased to reach the maximum average value in the 5th month (P < 0.05); after slight oscillations between the 6th and 8th month, IGF-I concentrations increased in the 9th month (P < 0.05), decreasing until the end of gestation. FRUCT increased progressively and significantly from the 6th month of gestation, reaching the maximum values in the last month of gestation (P < 0.05). These results suggest that alternative mechanisms other than GH and IGF-I could be involved in the regulation of glycaemic metabolism in pregnant mare.

Fructosamine: An Alternative to Serum Glucose Measurement in White-tailed Deer (Odocoileus virginianus)

We determined the relationship between fructosamine and serum glucose in free-ranging white-tailed deer (Odocoileus virginianus) harvested during two seasonally stressful periods for deer in coastal North Carolina, US: July 2008 represented the postparturition and lactation period, and March 2009 represented the late winter and pre-green-up period. Serum glucose and fructosamine concentrations were similar between time periods but were uncorrelated within each season. However, when serum glucose was separated into high and low categories based on the median blood glucose score within each time period, we detected statistically significant differences between July and March for serum glucose. Fructosamine was more stable than serum glucose for evaluating the white-tailed deer physiologic condition.

Plasma fructosamine concentrations in horses with pituitary pars intermedia dysfunction with and without laminitis

REASONS FOR PERFORMING STUDY

Plasma fructosamine concentration ([fructosamine]) is believed to reflect medium term, average blood glucose concentration and in a previous study was higher in horses with active laminitis than in normal horses. Pituitary pars intermedia dysfunction (PPID) is associated with hyperglycaemia and laminitis.

OBJECTIVES

To test the hypotheses that: [fructosamine] is higher in PPID cases than normal animals; furthermore, that within cases of PPID [fructosamine] is higher in those with active laminitis than nonlaminitic cases and in cases that have been affected by active laminitis in the preceding year than those that have not.

STUDY DESIGN

Observational, case-control/cross-sectional study.

METHODS

[Fructosamine] was measured in cases of PPID (n = 46) and normal animals (n = 139). A normal range was calculated; values were compared between the 2 groups and within the PPID group, between cases with and without active laminitis and between cases that had and had not been affected by active laminitis in the preceding year.

RESULTS

In normal animals mean [fructosamine] was 248.7 μmol/l; the normal range (mean ± 2 s.d.) was 195.5-301.9 μmol/l. Plasma [fructosamine] was not higher in PPID cases than in normal animals. In PPID cases, [fructosamine] was significantly (P = 0.006) higher in cases with active laminitis (mean ± s.d. 261.2 ± 39.2 μmol/l) compared with those without active laminitis (234.5 ± 32.9 μmol/), but [fructosamine] was not higher in cases that had been affected by active laminitis in the preceding year than those that had not.

CONCLUSIONS

In horses affected by PPID, [fructosamine] is higher in cases with active laminitis than in cases without active laminitis.

POTENTIAL RELEVANCE

Clinical use of [fructosamine] is limited due to overlap with the normal range. Further studies into glucose and protein metabolism in cases of PPID are warranted.

Type 2 diabetes mellitus with pancreatic beta cell dysfunction in 3 horses confirmed with minimal model analysis

REASONS FOR PERFORMING STUDY

Type 2 diabetes mellitus (T2DM) is diagnosed rarely in equine practice although it may be under-recognised. A greater awareness of the condition and therapeutic considerations would be to the benefit of such cases presenting in practice. More investigation into the pharmacological management of these cases is needed.

OBJECTIVES

Three cases of diabetes mellitus were investigated using a specific test for insulin sensitivity and pancreatic beta cell function in order to define accurately and characterise the existence of T2DM in all 3 subjects.

METHODS

The insulin-modified frequently sampled i.v. glucose tolerance test was performed in each case and the data so obtained were subject to minimal model analysis of insulin-glucose dynamics. Cases were then monitored following treatment using a combination of dietary modification, metformin, glibenclamide and pergolide.

RESULTS

Marked insulin resistance was identified in each case and, furthermore, severe pancreatic beta cell dysfunction was present therefore classifying each case as end stage T2DM. Treatment was nevertheless associated with restoration of normoglycaemia in all cases.

CONCLUSIONS

T2DM in horses may be more common than generally considered.In some cases individuals may respond to therapy aimed at restoring insulin sensitivity and pancreatic function. Drugs used in other species for the treatment of T2DM have not yet been adequately tested in horses.

POTENTIAL RELEVANCE

T2DM should be considered as an important differential diagnosis in mature to elderly horses and ponies suffering from weight loss, polydipsia and polyuria. Clinicians should be encouraged to offer treatment and management advice when such cases are encountered.

Biochemical indices of vascular function, glucose metabolism and oxidative stress in horses with equine Cushing's disease

REASONS FOR PERFORMING STUDY

The mechanisms underlying the increased risk of laminitis in horses with equine Cushing's disease (ECD) are poorly understood.

HYPOTHESIS

That abnormalities in glucose homeostasis, similar to those which cause microvascular dysfunction in human diabetics, contribute to development of laminitis in horses with ECD.

METHODS

Thirty-one aged horses were divided into 3 groups based on clinical signs and dexamethasone suppression testing (DST). Group 1 (n = 12) had clinical ECD as evidenced by hirsutism. Group 2 (n = 10) had a positive DST but no hirsutism. Group 3 (n = 9) were controls without ECD, with a negative DST and no clinical evidence of ECD. Biochemical indices of glucose metabolism, vascular function and oxidative stress were determined in single morning blood samples.

RESULTS

Group 1 had abnormalities in glucose homeostasis, including increased levels of glucose and insulin, compared to Groups 2 and 3. Groups 1 and 2 had significantly lower plasma thiol (PSH) levels and nonsignificantly lower albumin-corrected PSH levels than Group 3, consistent with oxidative stress.

CONCLUSIONS AND POTENTIAL RELEVANCE

The observed abnormalities in glucose metabolism and oxidative stress could potentially contribute to development of laminitis in horses with ECD, by similar mechanisms to those that cause microvascular dysfunction in human diabetics. The absence of inter-group differences in the biochemical indices of vascular function precludes their use as preclinical diagnostic indicators of vascular dysfunction. The study also highlighted limitations in the premortem diagnosis of ECD.

Glucosuria in captive okapi (Okapia johnstoni)

Eighteen of 38 captive okapi housed in the United States were found glucosuric by dipstick analysis. To confirm these findings, urine glucose concentrations of captive okapi from one collection (n = 10) were analyzed by two methods: urine dipstick analysis and quantitative analysis. Seven of these urine samples were positive for glucose by dipstick, with comparable glucose measurements by quantitative analysis. For a presumed normal control, okapi (n = 10) held in captivity within their native home range were tested for glucosuria by urine dipsticks; all were negative. Serum fructosamine (221-362 micromol/L) and insulin (9-45 pmol/L, 1.17-5.85 microU/ml) concentrations were determined from okapi (n = 6) with and without glucosuria with the use of results considered within normal limits for other ruminants. We conclude that glucosuria is a true finding in many apparently healthy captive okapi in the United States.

Serum Fructosamine Concentrations in 59 Dogs Naturally Infected with Angiostrongylus vasorum

Retrospectively, 89 cases of dogs infected with Angiostrongylus vasorum were examined. Fifty-nine of these 89 dogs fulfilled the criteria of not being dually infected with Crenosoma vulpis as well as having a full biochemistry profile including serum fructosamine available. The mean serum fructosamine value of the 59 dogs was 236 micromol/l (reference value 258-348 micromol/l) and significantly lower than the serum fructosamine level of 314 micromol/l in a control group of 42 clinically healthy dogs. Eleven dogs were available for follow up after successful treatment of angiostrongylosis. In this group, the serum fructosamine value rose from a mean of 244 micromol/l to a mean of 320 micromol/l following treatment. Serum glucose, albumin and protein were all within the respective reference ranges at all sampling points. The results indicate that serum fructosamine could be affected by infection with A. vasorum. Furthermore, this change cannot be explained by measurable changes in the level of glucose, albumin or protein. The clinical impact of this study is that a low fructosamine value may indicate infection with A. vasorum thereby suggesting a Baermann test to be performed.

Small strongyle infection: consequences of larvicidal treatment of horses with fenbendazole and moxidectin

The study was undertaken to evaluate adverse effects of larvicidal treatment in horses naturally infected with cyathostomins. Out of 24 ponies kept on pasture, four animals were housed in September and anthelmintically cured to serve as worm-free controls (group C-0). The others were housed in December. Eight animals each were treated 8 weeks later with 5 x 7.5mg/kg fenbendazole (FBZ) or 1 x 0.4 mg/kg moxidectin (MOX). Four animals remained untreated (group C-i). Two, 4, 6 and 14 days after the end of treatment two animals of each of the treated groups were necropsied together with group C-0 and C-i animals. Infected animals before treatment showed weight loss, eosinophilia, increased plasma protein and globulin contents. Treatment was followed by weight gain and temporal plasma protein and globulin increase. Proportions of CD4+ and CD8+ T lymphocytes in the peripheral blood did not differ between the groups before treatment but dropped significantly temporally after FBZ treatment. Group C-0 was worm-free at necropsy. Group C-i animals contained variable numbers of luminal and tissue cyathostomins. Histological sections showed larval stages in the lamina propria und submucosa surrounded by macrophages. Either treatment was effective against luminal parasites and reduced the number of larvae in the bowel wall beginning 4-6 days after FBZ and 6-14 days after MOX treatment. Histologically, as a first reaction after FBZ application T lymphocytes accumulated around morphologically intact L4 in the submucosa. Subsequently T lymphocytes associated with eosinophils infiltrated the submucosa. Parasites became enclosed by granulomas with eosinophils adhering to and invading the larvae which started to disintegrate on day 4. Later on, particularly on day 14 inflammation extended into the mucosa and was frequently associated with ulcerations. Third stage larvae in general and L4 in the lamina propria, however, seemed not to be affected until day 14 and even then, parasites did usually not generate extensive inflammation. After MOX treatment severe morphologically detectable alterations of tissue larvae could not be observed earlier than day 14. Different from FBZ treatment, larvae disintegrated and were obviously resorbed without causing severe inflammation in the gut wall. In conclusion treatment with either drug was efficacious against tissue larvae of cyathostomins but there may be different clinical consequences: in contrast to MOX effects, killing of larvae due to FBZ was associated with severe tissue damage, which clinically may correspond to reactions caused by synchronous mass emergence of fourth stage larvae, i.e., may mimic larval cyathostominosis.

Evaluation of a continuous glucose monitoring system for use in veterinary medicine

BACKGROUND

With the emergence of continuous glucose monitoring systems being used to provide a detailed glucose picture in humans, a commercially available system (CGMS(R), Medtronic Minimed, Northridge, CA) was examined for use in veterinary species.

METHODS

Adult, clinically normal horses (n = 7), cats (n = 3), dogs (n = 4), and cows (n = 5) were studied. Cats (n = 4), dogs (n = 5), and one horse with diabetes were included in the study. Several of the normal horses, including the horse with diabetes, and one cow were subjected to an intravenous glucose tolerance test. The CGMS was attached to each animal, and the recorded interstitial glucose concentrations were compared with whole blood glucose concentrations as determined by a point-of-care glucose meter. Events such as insulin administration, feeding, travel, or administration of intravenous glucose were all noted and compared with results from the CGMS.

RESULTS

There was a positive correlation between interstitial and whole blood glucose concentrations for all the clinically normal species, those with diabetes mellitus, and those receiving intravenous glucose. Events such as feeding, glucose or insulin administration, and transport to the clinic were noted by the owner or clinician and could be identified on the graph and correlated with time of occurrence.

CONCLUSIONS

Our data indicate that the use of the CGMS is valid for use in the species examined. Use of this system alleviated the need for multiple blood samples and the stress associated with obtaining those samples. This system may provide greater monitoring capabilities in patients with diabetes and promote the diagnostic and research potential of serial glucose monitoring in veterinary species.

Evaluation of a continuous glucose monitoring system for use in dogs, cats, and horses

OBJECTIVE

To evaluate a continuous glucose monitoring system (CGMS) for use in dogs, cats, and horses.

DESIGN

Prospective clinical study. Animals-7 horses, 3 cats, and 4 dogs that were clinically normal and 1 horse, 2 cats, and 3 dogs with diabetes mellitus.

PROCEDURE

Interstitial glucose concentrations were monitored and recorded every 5 minutes by use of a CGMS. Interstitial glucose concentrations were compared with whole blood glucose concentrations as determined by a point-of-care glucose meter. Interstitial glucose concentrations were also monitored in 2 clinically normal horses after oral and i.v. administration of glucose.

RESULTS

There was a positive correlation between interstitial and whole blood glucose concentrations for clinically normal dogs, cats, and horses and those with diabetes mellitus. Events such as feeding, glucose or insulin administration, restraint, and transport to the clinic were recorded by the owner or clinician and could be identified on the graph and associated with time of occurrence.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data indicate that use of CGMS is valid for dogs, cats, and horses. This system alleviated the need for multiple blood samples and the stress associated with obtaining those samples. Because hospitalization was not required, information obtained from the CGMS provided a more accurate assessment of the animal's glucose concentrations for an extended period, compared with measurement of blood glucose concentrations. Use of the CGMS will promote the diagnostic and research potential of serial glucose monitoring.

Serum fructosamine concentrations in dogs with hypothyroidism

Serum fructosamine concentrations were measured in 11 untreated hypothyroid dogs with normal serum glucose and serum protein concentrations. The fructosamine level ranged between 276 and 441 micromol/L (median 376 micromol/L; reference range 207-340 micromol/L). Nine of the 11 dogs had fructosamine levels above the reference range. The fructosamine levels decreased significantly during treatment with levothyroxine. It is suggested that serum fructosamine concentrations may be high in hypothyroid dogs because of decelerated protein turnover, independent of the blood glucose concentration.

Pathogenicity of cyathostome infection

Cyathostomes are now the principle parasitic pathogen of the horse: a remarkable transformation during the last 25 years from virtual obscurity to focus of attention in equine parasitology. This rise to prominence coincides with the marked decrease in prevalence of large strongyle infections as a result of widespread use of modern anthelmintic compounds. On the basis that strongyle-associated diseases continue to commonly occur in the absence of these large strongyle species, clinical attention has turned to the pathogenicity of cyathostomes. Although many horses harbour burdens of tens of thousands of cyathostomes without developing detectable illness, these parasites can result in an inflammatory enteropathy affecting the caecum and colon. Although the principle clinical effect of cyathostomosis is weight loss, affected individuals may exhibit other signs including diarrhoea and/or subcutaneous oedema and/or pyrexia. Clinical cyathostomosis occurs more commonly in young horses in late winter/early spring but there is lifelong susceptibility to cyathostomes and they can cause clinical disease in any age of horse during any season. Animals with cyathostomosis often develop hypoalbuminaemia and/or neutrophilia but there are no clinicopathological features specific for the disease. Experimental infections with cyathostomes have resulted in both clinical and pathological features similar to those of naturally-occuring cyathostomosis cases. From the experimental infection studies, it is evident that cyathostomes are pathogenic at times of both penetration into and emergence from the large intestinal mucosa. An unusual feature of cyathostome biology is the propensity for arrested larval development within the large intestinal mucosa for more than 2 years. From limited studies it appears that this arrested larval development is favoured by: feedback from luminal to mucosal worms; larger size of challenge dose of larvae and trickle (versus single bolus) infection. During arrested larval development cyathostomes have minimal susceptibility to all anthelmintic compounds, thus, limiting the effectiveness of therapeutic and/or control strategies. Although, the relative importance of individual cyathostomes is not known, the development of species-specific DNA methods for identification of cyathostomes provides a means by which the pathogenicity of different species might be established.

The pathogenic effects of experimental cyathostome infections in ponies

Nine pony breed foals were reared indoors, then allocated to one of three groups infected with either 3.9 million (Group A) or 3.15 million (Group B) cold-conditioned third stage cyathostome larvae or kept as uninfected controls (Group C). The larvae were administered as a 'trickle' infection of 150000 larvae per dose, three times weekly. Blood biochemical and haematological analyses were performed weekly and faecal worm egg counts bi-weekly. Complete parasitological examinations were performed on all ponies at various times post-initial infection (PI): one infected animal at 9 weeks PI, four animals (three infected, one control) at 20 weeks PI and four animals (two infected, two controls) at 60-62 weeks PI. All ponies in the infected groups experienced a marked reduction in weight gain and two animals developed clinical disease: one pony developed intermittent diarrhoea and colic 8 weeks PI; another pony developed intermittent diarrhoea between 30 and 52 weeks PI. All infected ponies had decreased serum fructosamine concentrations and five had decreased serum albumin, which were first apparent 4-6 weeks PI. Alterations in the composition of serum globulins were detected in all ponies. Transient neutrophilia was observed in five animals from the infected groups 3-9 weeks PI. Serum alkaline phosphatase concentrations were increased in one pony between 30 and 60 weeks PI. During the course of the experiment, faecal samples from all infected animals were negative for worm eggs. At necropsy, cyathostome larvae were present within the mucosa of the large intestine of all infected ponies, however the mucosal larval counts varied considerably between individuals.